Gas turbine engines typically include one or more shafts supported by bearings. The bearings are housed in bearing chambers where oil is supplied to the bearings for lubrication and cooling. To prevent some of the oil from leaking out of such a bearing chamber, seals are provided between the bearing chamber and the shaft. Under normal operating conditions, the pressure outside of the bearing chamber is intentionally kept higher than the pressure inside of the bearing chamber so that there is a positive pressure differential across the seals. This positive pressure differential can prevent oil from exiting the bearing chamber via the seals. However, excessive wear or of failure of a seal could potentially cause oil leakage from the bearing chamber via the worn or failed seal.